Multiple cartilaginous exostoses

Classification according to ICD-10
Q78.6	Congenital multiple exostoses - Multiple cartilaginous exostoses
ICD-10 online (WHO version 2019)

Multiple cartilaginous exostosis is the name for an autosomal - dominant inherited disorder with numerous benign cartilage-covered bone tumors. Since these are osteochondromas , which are covered with hyaline cartilage instead of fiber cartilage, the term "cartilaginous" exostosis is actually incorrect. With an incidence of about 1: 50,000, exostosis is one of the most common bone tumor diseases , affecting women and men equally. Around 70% of the patients have a familial form, around 30% have a sporadic form, i.e. a new mutation.

At the time of birth, exostoses are still very rare; they occur mainly in childhood and adolescence, right up to the end of the growth plates . During this time, the exostoses also increase in size. After the end of growth, no further exostoses form, and a later increase in size is then a sign of malignant transformation ( degeneration ), i.e. H. Transformation into a malignant bone tumor. A secondary chondrosarcoma occurs in about 3 - 5% .

The exostotic disease can rarely be completely asymptomatic, but its manifestation ( phenotype ) is highly variable, even in a family. In about 19% there are a maximum of five exostoses, in about 19% there are more than twenty.

In general, the clinical problems are characterized by deformities and functional limitations, which results in the clinical division of the expression according to Pedrini into three classes and two subgroups each:

• 1 - No deformities and no functional restrictions (38%, 1A - a maximum of five exostoses, 1B- more than five exostoses)
• 2 - deformities, but no functional restrictions (37%, 2A - a maximum of five deformities, 2B - more than five deformities)
• 3 - deformities and functional limitations (25%, 3A - maximum one functional limitation, 3B - more than one functional limitation)

Since the exostoses start metaphysically near the growth plates, they are often found near the joints and lead to movement restrictions, off-axis growth with deformities and hypoplasia (short stature) of individual bones up to a general short stature. Typical misalignments are:

• Length differences in the area of ​​the extremities ( leg length difference )
• Axial deviations in the area of ​​the knees and ankles genu valgum
• Asymmetries of the shoulder and pelvic girdle ,
• Subluxation of the hip joint as a result of the femoral head being forced out through the femoral neck, which widens exostotically in the medial direction
• Ulnar deviation of the wrist due to ulnar shortening with subsequent curvature of the radius in the direction of the too short ulna with subluxation of the radiocarpal joint .

The exostoses can also disturb in the immediate vicinity and compress nerves, vessels or tendons and thus trigger pain and motor problems.

Sometimes there is also a permagna parietal foramina .

genetics

Exostosis is almost always due to a mutation in one of the two genes EXT1 (65%) or EXT2 (25%). As a rule, the mutations lead to shortened and completely or partially functionless EXT proteins. The two EXT proteins are ubiquitous transmembrane glycoproteins that are involved in the elongation of heparan sulfate glycosaminoglycan chains (HS-GAG) of the matrix proteoglycans , which in turn play an important role in cell growth and the differentiation of cartilage cells play.

treatment

The treatment depends on the disorders and includes pain therapy, physiotherapy and surgical interventions to remove annoying exostoses and to correct deformities. However, the results are not always satisfactory, especially with multiple operations.

Synonyms

Legs of a 26 year old patient

multiple osteochondromas in the pelvic area, x-ray

• Ecchondrosis ossificans
• multiple osteochondromatosis
• multiple hereditary exostoses (MHE)
• hereditary multiple exostoses (HME)
• Exostotic disease
• multiple osteochondromas
• exotic dysplasia
• Osteoplasia exostotica
• multiple osteomatosis
• dominantly hereditary chondral osteomas
• multiple cartilaginous exostoses (Engl.)
• Bessel-Hagen disease

Individual evidence

1. ↑ F. Hefti: Pediatric Orthopedics in Practice . Springer-Verlag, Berlin 1997, ISBN 3-540-61480-X .
2. ^ GA Schmale, EU Conrad, WH Raskind: The natural history of hereditary multiple exostoses. In: The Journal of Bone & Joint Surgery . Volume 76, Issue 7, 1994, PMID 8027127
3. ↑ E. Pedrini et al .: Genotype-phenotype correlation study in 529 patients with multiple hereditary exostoses: identification of "protective" and "risk" factors. In: J Bone Joint Surg. 2011; 93-Am, pp. 2294-2302.
4. ↑ JR Stieber, JP Dormans: Manifestations of hereditary multiple exostoses. In: Journal of the American Academy of Orthopedic Surgeons . 2005; 13 (2), pp. 110-120. PMID 15850368
5. ^ Exostoses, Multiple, Type II.  In: Online Mendelian Inheritance in Man . (English)
6. ↑ Osteochondromas, multiple. In: Orphanet (Rare Disease Database).

Web links

Commons : Osteochondroma  - Collection of pictures, videos and audio files

• Patient-oriented description
• Multiple Cartilaginous Exostoses -Clinic and Therapy-

This article is about a health issue. It is not used for self-diagnosis and does not replace a diagnosis by a doctor. Please note the information on health issues !